Insulation
R-Value Calculator
Total R-value and U-value of a wall or roof build-up, layer by layer.
R = thickness ÷ conductivity
Also called u value calculator · thermal resistance calculator
Home & Construction · 4 calculators
Insulation Calculators
R-value and U-value of assemblies, heat loss, insulation thickness, batts and rolls needed, and annual energy loss.
Insulation
Heat Loss Calculator
Heat loss from a room through fabric and ventilation, and the heating power it needs.
Q = (Σ U×A + 0.33 × ACH × volume) × ΔT
Also called heat loss calculation · room heat loss
Insulation
Insulation Thickness Calculator
Insulation thickness needed to reach a target U-value or R-value for a given material.
thickness = (target R − existing R) × con…
Also called how thick insulation · insulation depth calculator
Insulation
Insulation Calculator
Insulation rolls or boards needed for a loft, wall or floor, with the cost and energy saving.
units = area × (1 + waste) ÷ coverage per…
Also called loft insulation calculator · how much insulation do i need
Key insulation formulas
| R-Value | R = thickness ÷ conductivity · U = 1 / ΣR |
|---|---|
| Heat Loss | Q = (Σ U×A + 0.33 × ACH × volume) × ΔT |
| Insulation Thickness | thickness = (target R − existing R) × conductivity |
| Insulation | units = area × (1 + waste) ÷ coverage per unit |
Insulation questions
What is a good U-value for a wall?
Modern new-build walls typically need 0.18 W/(m²·K) or better; an uninsulated solid brick wall is around 2.0.